We are given
The average income, I, in dollars is

(a)
now, we are given
average income is $275000
so, 
now, we can set them equal
and then we can solve for x


we will have to use quadratic formula


we get


we need to find youngest age
It means that we need to choose smallest value
so,
............Answer
(b)
we are given
x=40
so, we can plug it and find I

..............Answer
546 - 525 = 21
21 is 4% of 525.
Lisa gained a 4% pay increase.
Set up and solve an equation:
3(90-x) = (180-x). Then 270 - 3x = 180 - x, or 270 - 180 = 2x.
90 = 2x, so x = 45 deg.
Is this true? 3(90-45) = (180-45)? If so, x = 45 degrees is correct.
$5000 I think should be right